Various continuous vapor adsorption processes have been developed utilizing an adsorber wherein one or more bed comprising adsorbent media is utilized for capturing VOCs and other contaminates from a gas stream. In these systems, a gas stream is fed into the adsorber wherein contaminants from the gas stream are captured in the adsorbent media. After the contaminants are adsorbed, the loaded adsorbent media passes through a regenerator wherein the loaded adsorbent media is heated and the contaminants are released. After regeneration, the heated adsorbtion media is returned to the adsorber to be reused for capturing contaminates from the gas stream.
Typically, the rate of heated adsorbent media returning to the adsorber is small relative to the rate of the inlet gas fed into the adsorber. In such a process, the gas feed stream cools the heated regenerated adsorbent media such that the temperature increase to the adsorbent beds is acceptable and does not affect the capacity of the adsorbent to remove contaminates.
However, in the case of natural gas liquid (NGL) separation from a natural gas stream the concentration of heavier hydrocarbons is high. In this case the rate of hot adsorbent fed into the adsorber from the regenerator may be large compared to the feed rate of the natural gas stream. In such a case, the temperature of the adsorbent bed may be too high for effective NGL adsorbtion.
There is a need for an improved adsorptions process for recovering condensable components such as NGLs from a gas stream, particularly, a natural gas stream.